Drying kiln



July 17, 1923; 1,462,194

C. A. CUTLER DRYING KILN Filed Dec. 27, 1920 4 Sheets-Sheet 1 July 17, 1923.

c. A; CUTLER DRYING KILN Filed Dec. 27, 19,20

1 4 Sheets-Sheet 2 C. A. CUTLER DRYING KILN Filed Dec. 2'7, 1920 4 Sheets-Sheet 4 Patented July 17, 1923.

UNITED STATES PATENT OFFICE. I v

CLIFFORD A. CUTLER, or BUFFALO, NEW YORK.

' DRYING KILN.

Application filed December 2' 7, 1920. Serial No. 483,807.

ments in Drying Kilns, of which the ollowing is a full, clear, and exact' description;

It is well known'to those skilled the art, that in order to properly dry any, product or material in the least possible time,

, it is necessary that the temperature and been, therefore, to provide a kiln which humidity conditions of the drying medium, best suited to the dryin of the" product or material, be secured an maintained at all points within the drying chamber. Moreover, it is known that such conditions can be secured and maintained only by providing a very rapid, properly directed,and even movement of the drying medium everywhere within the kiln. i v p n The principle objectof my invention has shall embody the above advantages, and by which materials may be evenlyjand economically dried in the; shortest possible time, and in such a manner as to preserve the quality of thematerials. Another object has been to provide a kiln which shall be simpleto manufacture, having combined means for heating, humidify ing, de-humidifying and purifying the 'drying medium. Y I

Another object has been to provide a kiln in which the foul. gases of fumes coming from the product or material being dried shall t0 taken out of the drying medium, without losing any appreciable amount of the drying medium, and preventing any retardation of the drying process.

Another object has been to provide a kiln which shall be so simple in its construction that itmaylb'e easily and quickly installed, and onei'n which repairs or replacements may be easily mader The above objects andadv nmges have been 'accomplishedbythe device shown in the accompanying drawings inwhichI have shown myidevice asapplied to 'the drying of lumber, it being obvious that it may be advantageously used "forfdryin 'g' various vegetable, animal, mineral,- or Cl'1eII 1ICal products. In thedrawings: Fig. 1' shows a s1de,-sect1onal elevation of one .form of my device and 1s taken on line 1-1 of Fig. 3, forconvenience of illusfresh air duct: 21.

V Fig. 4. I .Fig. 6 shows another form of my invention. l

'Fig. 7 is an end, sectional, view of a moditied form of kiln.

Fig. 8 is a reduced, sectional, plan view of the form shown in Fig. 7.

Referring particularly to Figs. 1 to 3, inelusive, my kiln comprises two side Walls 10, a rear end wall 11 and a front end-wall 12. 13 is theroof of the kiln, and 14 is the floor thereof. Arranged on each side ofa central space 15 is a delivery duct16, each duct being separated'from the space 15 by means of a duct wall 17. A return duct 18 isarranged'at one side ofeach of the delivery ducts 16 and a duct wall 19 separates each of theseducts from the ducts 16. A

duct wall 20 is arranged at the outside of each of the ducts 18 and in spaced relation with the wall 10. Between each of the duct walls 20 and the side walls 10 is provideda The central space '15, and-the delivery ducts 16 and return ducts 18 extend the entire length of the kiln and terminate at the rear wall 11 and front wall 12. The fresh air ducts extend from the rear wall 11 and pass through the front wall 12 where each terminates in a pit 22, each of which is open to the atmosphere. The ducts 16, 18 and 21 are enclosed by means of duct covers 23, which are disposed over the duct walls 17, 19 and 20 and extend from the walls 17 to the side walls 10. The duct covers 23 form a false floor for the kiln, and upon it are suitably'supported two pairs of T- shaped rails or tracks 24. These tracks ex all the surfaces of each piece of lumber.

A baffle plate or curtain 27 is suspended from the roof 13 of the kiln and extends down in front of the opposite side faces of the two stacks of lumber,-thus preventing the currents of air, which come up between the stacks of lumber, from passing over the top thereof, as hereinafter described.

A plurality of openings 30 are provided atsuitable intervals throughout the length ofthe duct walls 17. These openings connect the delivery ducts 16 with the central space 15. Deflectors 31 control the effective size of the openings 30. These deflectors are arranged in front of the openings 30 and extend preferably into the delivery ducts 16, thus serving to apportion the amount of drying medium which'is admitted to each of the openings 30. The deflectors 31 are preferably adjusted so as to evenly distribute the flow of air through the openings 30. Arranged in the central space 15 and disposed in front of each of the openings 30 is a radiator 32, which provides means for heating the drying medium as it comes from the openings 30 and before it is passed through the material being dried. A plurality of ports 33 are provided through each of the duct covers 23 and communicate with the space 47 at the lateral, outside surfaces of the piles of lumber 26. These ports 33 are graduated in size and are disposed in .a manner opposite to the arrangement of the effective areas of the openings 30, i. e., the largest port 33 is at the end of the duct which is farthest from the blower 34, while the smallest port is at the end nearest the blower.

48 is an operating room which is adjacent the rear wall 11 and in which the blowers 34 are located. The suction side of each of these blowers is connected with one of the return ducts 18, and the discharge side of each is connected with one-of the delivery ducts 16. The blowers are preferably mounted on or attached to a single shaft 3'5,

whereby they may be conveniently driven by a motor 36. 37 is the steam supply line which is connected. with the two series of.

tends into each of the return ducts 18, pref-- erably'close to the blower end thereof, and 44 is an open T-fitting. This pipe 43 is connected with the steam line 37 by means of'piping 45 and a hand-controlled valve 46, bymeans of. which the humidity of the dryin medium may be easily controlled. Suita 1e steam traps are, of course, provided for taking care of the condensation occurring in the radiators 32, as well as in the steam pipe lines 43.

Arranged at each side of the kiln and extending the length thereof is a curtain wall or porous de-humidifier 50. These dehumidifiers are suspended from the roof 13 of the kiln so that the lower edge of each will terminate at a point immediately above each of the duct walls 20. A lurality of ports 51 are provided through each of the duct covers immediately above the fresh air ducts 21. These ports connect the fresh air duct with the fresh air passageway 52, provided between each of the outer walls 10 of the kiln and the de-humidifiers 50. A plurality of stacks 53 is provided on the roof of the kiln which are so arranged as to communicate with the fresh air passageways 52, whereby a draft of fresh air is created through the passageways 52 and the fresh air ducts 21.

Referring now to the form of device shown in Figs. 4 and 5, 56 are the stacks of lumber which are placed upon trucks 57 supported on tracks 58, suitably arranged some distance above the floor line 59 of the kiln. 60 are the side walls and 61 the roof of the kiln. This structure is very similar to the one hereinbefore described except that the discharge ducts 62, the return ducts 63 and the fresh air ducts 64 are preferably-made of metal and placed upon the floor of the kiln. The discharge ducts 62 are provided with ports 65,. in front of each of which a radiator 66 is located. Each of the return ducts 63 is provided with ports 67 along its upper face. Each fresh air duct 64 is arranged adjacent a return duct 63, and it'is also provided with ports 68 for the passage of fresh air. The fresh air ducts 64 preferably open into the atmos phere through one of the end walls of the kiln. 69 are the porous (lo-humidifiers of the device, each of which is supported from the ceiling 61 and is suspended immediately over the middle partition of each pair of ducts 63 and 64. The openings 67 and 68 in the ducts 63 and 64, respectively, are thereby separated. The de-hu'midifier forms a fresh air passageway 70 at the upper end of each of which is provided a su1table ventilator 71, for creating a draft of air through the passageway 70.

72 are the blowers, the suction side of each of which is attached to one of the return ducts 63, and the delivery side of each of which is attached to one of the delivery ducts 62. A separate motor 73 is preferably provided for each of the blowers. A steam pipe 74 with a hand controlled valve 7 5 is preferably attached to the suction side of each of the blowers, and provides means whereby the drying medium will be properly humidified. Suitable steam supply piping 76, and suitable exhaust steam pip- 6, 80 are the-fresh air ducts which are-sep-.

.-'the central space between the piles o lumher.

In the form of the device shown in Fig.

arated, fromvthe interior'of the kiln by means of the porous de-humidifiers 81. 82 are the return "ducts, which are connected to the suction side of the blowers 83. Each of these ducts is provided with a plurality of openings 84 in its upper wall. 85 is the delivery duct which is centrally arranged between the piles of lumber 86 and is provided with a plurality of openings 87. 'The blowers 88 are preferably connected together and driven by a motor 88. The discharge pipes of these blowers are connected together and to the delivery duct 85.

In Figs. 7 and 8, I show a form of my invention in which the discharge and return ducts have been omitted. In th%e figures, 90 are the fresh air passageways which are provided by the outer walls 91 oflthe kiln and the porous (ls-humidifiers 92. Regulatable openings 93 are arranged through the walls 91 near the floor line for admitting fresh air-to the passageways 90, and openings 94 are arranged through the walls near the top of the kiln for creating a circulation of'fresh air through the passageways 90. The piles of lumber 95 are arranged some distance above the floor of the kiln as in the form shown in Figs. 4- and 5, and a centrally arranged pipe 96 extends longitudinally of the kiln and provides means for projecting moisture into the space between the piles of lumber 95. 97 are the steam radiatois which are provided with suitable piping for steam supply and drainage. ()ppositc each of the radiators 97, is arranged an independently operated fan 98, whereby air is made to cir culate through the radiators and upwardly through the space between the piles of lu1nber. (oncave deflecting plates 99 are provided for deflecting the drying-medium up- Wardly.

The operations of the several forms of my invention are quite similar; and, for clearness and briefness of description, I will refer only to the operation of the form shown in Figs. 1 to 3. inclusive.

When the blowers 34 are set in operation, currents of air will be drawn through the ports 33 into the return ducts 18 and dis charged into the delivery duct 16, through the openings 30 in the wall 17 thereof; through the radiators 32 and upwardly through the central spa-ce 15, where it will pass the recording thermometer billb- 41 and the thermostatic regulator bulb 42 of the thermostatic temperature control. Inasmuch as the baffle curtains 27 prevent the drying medium from passing over the top of the piles 26, it will be obliged to pass between the layers of lumber and out at the lateral, outside surface of each pile. After the fans have. been started, the valve 46 is operated to admit steam into the return ducts 18 through the open tees 4t thereby properly humidifying the drying medium. As the drying medium is being forced along through the delivery duct 16, the deflectors 31, arranged in front of the openings 30, will, apportion an equal amount of drying medium for each of these openings 30 and thereby cause aneven distribution of the medium. The passage up through the central space between the piles of lumber will be very rapid; and, as the drying medium passes between the layers of material, it exchanges a portion of its heat for the moisture of the material. This exchange tends to reduce the temperature and increase the humidity of the drying medium as it passes from one side of the pile of lumber to the other. However, the movement of the drying medium in my kiln is so rapid and uniform at all points in the drying-chamber that this tendency is reduced to practically a minimum. In my kiln, therefore, the material is dried at the same rate atthe outer edges of the piles as at the inner edges thereof. This not only results in a great saving of time, but produces the greatest possible uniformity of finished product which is of the highest quality. As the drying medium comes from the outer edges of the piles of lumber, it contacts with the porous tie-humidifiers 50, which, being of fabric, extracta predetermined amount of vapor from the drying medium without allowing an appreciable amount thereof to escape from the kiln. This feature permits of a very eliicient and economical operation. The vapor which passes through the porous de-humidifiers 5t). enters the fresh air passageway 52. and mixes with the air contained therein, after which it is removed from the passageway by the constant circulation of fresh air therethrough. is As the drying medium is de-humidified by the porous (lo-humidifiers 50, it is slightly cooled by contact with the (lo-humidifier. This cooling renders the medium heavier, causing it to fall toward the ports 33 in the return ducts 18. This movement adds appreciably to the velocity and uniformity of flow of the drying medium, since this effect is in the direction of the forced,circulation. Due to the combined action of the blowers 34 and the cooling effect of the medium, just referred to, the de-humidified drying medium is drawn downwardly with great velocity and through the openings 33. Thence it is (onducted through the return duct 18 and again forced into the delivery duct 16 by the blowers. It will thus be seen that in the operation of my kiln the drying medium is constantly recirculated, the only loss being that of a. slightjamount of heat due to the'contact of the medium with the de-humidifiers 50 as the surplus moisture is being taken from the medium. Thismakes the operation of my kiln highly ethcient as well as economical. Moreover, the operation of my kiln is entirely independent-of outside atmospheric conditions. Durlng the drying of some materials, fumes and gases are given off which may be detrimental to the drying proress. The de-humidihers 50, being porous. allow these gases and fumes to pass theretlu'ough and into the fresh alr passage-ways 52 without permit-ting any appreciable amount of drying medium to escape. By this means the drying medium is kept pure, and the drying operation 18 not retarded by the presence of any detrimental fumes or gases.

Vhile I have shown. and described my device as used in connection with the drying of lumber, it is obvious that it is equally efficient in the drying of many other materials, and that, therefore, the specific arrangement and location of parts may be varied as required to meet difierent conditions. arrangement for accommodating two piles of work-pieces, each adjacent to the other and with a space therebetween. While this is the preferable form of my invention, clearly, only one pile of work-pieces may be provided for.

These and other modifications of the details herein shown and described may be made without departing from the spirit of my invention or the scope of the appended claims; and I do not, therefore, wish to be limited to the exact embodiment herein shown and described, the form described being merely a preferred embodiment thereof.

Having thus described my invention, what I claim is:

1. A drying kiln comprising non-porous kiln walls, and porous ehumidifiers, lo-

cated in spaced relation with the kiln walls.

2. A drying kiln comprising non-porous kiln walls, porous tie-humidifiers, located in spaced relation with the walls, and a plurality of heating units, located below the work-piece.

3. A drying kiln comprising non-porous kiln walls, porous dehumidifiers, located in spaced relation with the walls,-a plurality of heating units, located below the workpieces, and means for forcing air through the heating units. g,

4. A drying kiln comprising nonporous spaced relation with the walls, a plurality of heating units, located below the workpieces, means for forcing air through the heating units and toward the center of the In the drawings, I have shown an space below such work-pieces, and means for directing the" air upwardly and centrally within the kiln.

5. A drying kiln comprising non-porous kiln walls, porous de-humidiliers, located in spaced relation with the walls, heating means, located below the work-pieces, and the work-pieces being so arranged as to provide an open, central space through which the-heated air rises.

6. In a drying kiln, the combination with work-pieces arranged in adjacent piles, having a central space therebetween, of nonporous walls, porous dehumidifiers in spaced relation with the walls, and a plurality of heating units, located below the piles of work-pieces.

T. In a drying kiln, the combination with work-pieces arranged in adjacent piles, having 'a central space therebetween, of nonporous walls, porous dehumidifiers in spaced relation with the walls, a plurality of heating units, located below the piles of workpieces, and deflecting plates depending from the top of the kiln and extending downwardly below the top of, and in contact with, one edge of each of the piles of workpieces.

8. In a drying kiln, the combination with work-pieces arranged in interspaced relation with each other and stacked in adjacent piles, having a central space therebetween, of non-porous walls, porous dehumidifiers in spaced relation with the walls, and a plurality of heating units, located belowthe piles of work-pieces.

9. A drying kiln comprising non-porous kiln walls, porous tie-humidifiers, located in spaced relation with the walls, and means for humidifying the air.

10. A drying kiln comprising non-porous walls, one or more porous de-l'iumidifiers in spaced relation with the walls, means for directing outside air into the space formed between the walls and the de-humidifiers, the walls of the kiln shutting oil the atmosphere from the drying space except as it may pass through the pores of the de-humidifiers, and heating means located in the space below the work-pieces.

11. In a drying kiln, the combination with work-pieces arranged in interspaced relation with each other and stacked in piles, of a plurality of heating units located below each pile of work-pieces, and means for forcing and recirculating air from a plurality of points through the heating units.

12. In a drying kiln, the combination with work-pieces arranged in interspaced relation with. each other and stacked in piles, of a kiln walls, porous de-humidifiers, located in plurality of heating units located below each pile of work-pieces, means for forcing air from a plurality of points through the heating units, deflecting plates depending from the top of the kiln and extending down helow the top of, and in contact with, one of the edges of each of the piles of workpieces.

13. In a drying kiln, the combination with work-pieces arranged in interspaced relation with each other and stacked in iles, of a plurality of heating units located low each pile of work-pieces, means for forcing air from a plurality of points through the heating units, bafiie plates' depending from the top of the kiln and extendin down below the top of, and in contact with, one of the edges of each of the piles of work-pieces, and means for directing the air upwardly along the side of the piles of work-pieces, having the battle plates, whereby the air will be passed into intimate contact with the workpieces.

14. In a drying kiln, the combinationwith work-pieces arranged in interspaced relation with each other and stacked in piles, of non-porous walls for the kiln. porous dehumidifiers in spaced relation with the walls, and heating units located below the piles of work-pieces.

15. In a drying kiln. the combination with work-pieces arranged in interspaced relation with each other and stacked in piles, of non-porous walls for the kiln. porous de-humidifiers in spaced relation with the walls, heating units located below the piles of work-pieces, and means for forcing air from a plurality of points through the heating units.

16. In a drying kiln. the combination with work-pieces arranged in interspaced relation with each other and stacked in piles, of non-porous walls'for the kiln, porous tie-humidifiers in spaced relation 'with the walls, heating units located below thepiles of work-pieces, means for forcing air froma plurality of points through the heating units. and means for directing the air upwardly along one side of the piles of work-pieces.

17. A drying kiln formed with a drying chamber. comprising dehumidifiers. inclosing the drying chamber and forming fresh air passageways between them and the outer walls of the kiln. fresh air ducts.. having openings communicating with the fresh air spaces, the kiln being formed with a central space, heating units arranged in the central space. the kiln being also formed,

below the work-pieces. with delivery ducts and with inlet ducts. the inlet ducts being in open communication with the interior of the kiln, along a point substantially adja cent to the de-humidifiers, and the delivery ducts being in open communication with the central space of the kiln, and means for along a point substantially adjacentto the de-humidifiers, the wall of the delivery duct. adjacent-the central space of the kiln, being formed with a plurality of openings, deflector plates for controlling the effective area of such openings. and means for drawing air from the return ductand forcing it into the delivery duct.

19. A drying kiln comprising non-porous kiln walls, porous de-humidifiers located in spaced relation with the walls, and a plurality of heating units.

20. A drying kiln comprising a floor, a false floor. the floors being in interspaced relation with each other, duct walls connecting the floors, whereby delivery and return ducts are formed. the false floor being formed with a plurality of air openings therethrough. means for forcing air through the ducts and air openings, and means for heating the air.

21. In a drying kiln. the combination of work-pieces arranged in adjacent piles. hav

ing a central space therebetween. of two kiln floors arranged in spaced relation with each other ductwalls connecting the floors. whereby delivery and return ducts are formed. the upper .fioor being formed with openings therethrough. means for forcing air through the ducts and the openings, and means for heating the air.

22. In a drying kiln. the combination with work-pieces arranged in interspaced relationwith each other and stacked in ad iacent piles. having a central space therebetween. of two kiln floors arranged in spaced relation with each other. duct walls connecting the floors, wherebv delivery and return ducts are formed, the upper floor being formed with openings therethrough. means'for forcing airthrough the'du-cts and the openings, and means for heating the air.

In testimony whereof, I have hereunto signed my name.

CLIFFORD A. CUTLER. 

